1. Field of the Invention
The present invention relates to a method of and an apparatus for gathering an end of a wide packaging sheet wrapped around a cylindrical article and pressing the gathered end into a hollow region in the cylindrical article, and more particularly to a method of and an apparatus for packaging a cylindrical article such as a roll of photosensitive material or thermosensitive recording material, for example.
2. Description of the Related Art
There have heretofore been proposed various packaging apparatuses for wrapping a cylindrical article with a wide packaging sheet and gathering opposite ends of the packaging sheet. For details of known packaging apparatuses of the type described above, reference should be made to Japanese utility model publication No. 2-1202, Japanese utility model publication No. 2-42564, and Japanese laid-open patent publication No. 2-109817.
The packaging apparatus disclosed in Japanese utility model publication No. 2-1202 and Japanese utility model publication No. 2-42564 use a packaging sheet whose opposite end dimensions are smaller than the radius of a cylindrical article to be packaged, and folds the ends of the packaging sheet along the ends of the cylindrical article. These publications are silent about an apparatus for using a packaging sheet whose opposite end dimensions are greater than the radius of a cylindrical article to be packaged, and gathering the opposite ends of the packaging sheet and forcing the gathered ends into a hollow region in the cylindrical article.
The packaging apparatus disclosed in Japanese laid-open patent publication No. 2-109817 use a packaging sheet whose opposite end dimensions are greater than the radius of a cylindrical article to be packaged, and gathers the ends of the packaging sheet. A suction pipe draws the packaging sheet when the suction pipe is positioned within a hollow region in the cylindrical article, so that an opening remains in the hollow region in the cylindrical article after the cylindrical article is packaged. In addition, the packaging sheet cannot strongly be gathered in the hollow region in the cylindrical article, and hence the hollow region in the cylindrical article cannot be sealed against entry of humidity, air, and light.
When photosensitive and thermosensitive recording materials are packaged, it is highly important to seal them particularly against entry of humidity and light.
It has been the customary practice to paste labels to the ends of or press plastic caps into the hollow regions in the packaged cylindrical articles for thereby sealing the hollow regions against entry of humidity and light.
The strength with which the ends of a packaging sheet are gathered is governed by the state of contact between a bent arm and a suction pipe which are used to gather the ends of the packaging sheet. However, since a rack and pinion mechanism is used to close the bent arm, a complex adjustment process is required to uniformize the contacting states of individual bent arms. Furthermore, since the thickness of the packaging sheet as it is gathered between the bent arm and the suction pipe progressively increases in the gathering process, the strength with which the ends of the packaging sheet are gathered is not stable.